The present invention relates to the door closure arts. It finds particular application in conjunction with a horizontal sliding door for sealing the opening to a sterilization chamber and will be described with particular reference thereto. It should be appreciated, however, that the invention is also applicable to a wide variety of other closure systems.
In many applications, it is desirable to have a chamber door sealingly engage a chamber opening. A gasket, positioned between the door and the outside of the chamber, creates an airtight seal between the door and chamber opening. For large chambers, such as steam sterilizers, horizontal sliding doors are sometimes used to allow the door to be moved from the open to the closed position. During translation, the door is guided to preclude scraping of the front of the chamber and avoid damage to the seal. When closed, the door is provided with some freedom of axial movement so that the door is able to move in and out a small amount as the pressure changes inside the sterilizer. Without this slack, the movement of the door would place stresses on the guidance system, leading to premature failure.
To provide this axial movement, the guidance system commonly includes a combination of rollers and recessed tracks. Unique bracketing is often needed to mount the rollers and unique tracks are generally provided which have the sole purpose of guidance. Additionally, because of the recesses, the guidance system does not provide guidance, and thus seal protection, for the entire door translation.
U.S. pat. No. 6,017,105 to Goughnour, et al. provides a sliding door guidance method for a walk-in sterilizer in which recesses in guidance tracks above and below the door receive guidance rollers at the top and bottom of the door when the door is in the closed position. The rollers must properly engage the recesses, otherwise pressure on the rollers when the door translates could cause damage to the rollers and associated hardware.
To ensure that the door of a sterilizer remains locked during a sterilization cycle, many sterilizers employ an electronic or pneumatically controlled locking mechanism which uses a program or pressure switch to determine when the lock needs to be applied. Such devices add to the complexity of the sterilizer.
The present invention provides for a new and improved guidance method for a horizontal sliding door which overcomes the above-referenced problems and others.
In accordance with one aspect of the present invention, a sterilization or disinfection apparatus is provided. The apparatus includes a housing which defines an interior chamber and an opening. A door has an interior face sized to seal the opening and an outer face. A horizontal support rail is mounted to the housing. A guidance assembly guides the door between an open position, in which items to be sterilized or disinfected are capable of being loaded into the chamber, and a closed position, in which the door covers the opening. The guidance assembly includes a pivotable support member, pivotally connected with the door. The pivotable support member is carried by the rail during opening and closing of the door.
In accordance with another aspect of the present invention, a method of guiding a sliding door between an open position, in which access is provided to the interior of a steam cabinet through an opening defined in the cabinet, and a closed position, in which the opening is covered by the door is provided. The method includes suspending the door from a pivotable support member which is pivotally connected with the door and rolling a roller which is rotatably connected to the pivotable support member along a horizontal track mounted adjacent the opening.
One advantage of the present invention is that the door is fully guided along the entire length of its travel.
Another advantage of the present invention is that the guidance system provides axial translation for pressure load reversals within the sterilizer.
Another advantage of the present invention is that the door locks automatically, in response to pressure changes within the chamber.
Another advantage of the present invention is that the motor drive cable and pulley door actuation system eliminates the need for a door obstruction sensor, thereby simplifying the design and providing an inherently safe system.
Still further advantages of the present invention will become apparent to those of ordinary skill in the art upon reading and understanding the following detailed description of the preferred embodiment.